DE 10 2006 004 146 A1 describes an electric toothbrush comprising a housing that functions as a handle and an electric motor that can move a bristle field carrier in the longitudinal direction of the housing as well as across its longitudinal direction with an oscillating action. The toothbrush is provided with a battery and a voltage stabilization circuit which supplies a stabilized power supply voltage to the electric motor.
DE 2 99 12 009 U1 describes an electric toothbrush having a drive with which the brush executes a rotating and reversing movement during tooth cleaning, whereby the rotational speed of the brush is either constant or is continuously variable.
DE 10 2005 063 045 A1 describes a discharge status display by means of which the almost discharged status of a battery can be recognized and displayed. The discharge status display comprises a display device designed as an LED, which lights up when the battery voltage drops below a certain threshold level.
With known battery-operated electric toothbrushes having a brush head that rotates with an oscillating action, the rotational speed of the drive motor changes with the voltage of the battery, i.e., when the battery is fully charged, the voltage and thus the rotational speed are much higher than when the battery has already supplied power for several tooth-brushing operations. The initially more rapid brushing movements of the bristles with new batteries because of the higher rotational speed are perceived as unpleasant in particular by users who have previously been using a manual toothbrush.
There thus exists a need for an electric toothbrush, which can be manufactured inexpensively and which is characterized by an operating performance that is perceived by the user as not requiring much adjustment.